v2 new feature - Cascade

On-site storage for commercial development frequently requires some
underground storage facility to handle runoff from frequent storm
event in order to reduce the frequency with which parking lot storage
may be an inconvenience.

The Cascade command lets you route the current inflow hydrograph
through a short cascade of storage cells formed from a variety of
cross-sectional shapes such as pipes, rectangular boxes, horizontal
and vertical elliptical pipes and pipe arch sections.

The current version of
the command is limited to only two elements. The data entry section is
self-explanatory to some extent. The form displays a number of columns
equal to the number of elements. The bottom row shows a drop-down list
from which the type of cross-section can be selected.

If any of the three special pipe sections are used (e.g. elliptical or
pipe arch) a second drop-down list on line 3 of the form is activated
to let you browse through a set of commercially available sizes. These
are shown in metric or imperial sizes depending on the choice of
units.

Apart from the overall dimensions of each element, you must define the
invert level and an orifice diameter and coefficient of contraction of
the outflow control from each cell. The orifice invert is assumed to
be the same as the invert of the upstream element.

Each iteration of the analysis requires two steps – first click on
[Setup Current Data] to enable the [Route] command and then click
[Route] to carry out the analysis.

The second row of the grid shows the peak values of the Inflow,
outflow from each cell and maximum depth in each element. If a cell is
surcharged, the data box containing the Height is highlighted to warn
you that more storage or a larger orifice is required.